I need help with Warship Hulls Unlimited type IX

[JWLaRue]

Re: I need help with Warship Hulls Unlimited type IX

Jay,

Perhaps the easiest way to determine how large the ballast tank needs to be is to put your sub in water and to trim it out for your preferred submerged trim. (e.g. periscope depth or perhaps with the top of the conning tower just barely out of the water) Then add floatation foam until the boat floats at the correct waterline.

The volume of the foam that you used to get it to surface trim is how large the ballast tank needs to be.

-Jeff

[subdude]

Re: I need help with Warship Hulls Unlimited type IX

Jay,

The method Jeff has told you is by far the easiest. One small addition. The foam you "add" to get the boat to surfaced waterline does not have to be "added", but can be in the form of foam blocks stuck under the keel. All you're trying to do is come up with a volume, not shapes or placement yet.

Jim

[flying jeep]

Re: I need help with Warship Hulls Unlimited type IX

That's what I did last time but I guess I made the pressure hull too big. So now where is my starting point? Most of the sub systems are based on a tube with a balast tank in the center. You don't have room to make your tank larger if it's already contained between two compartments. So do you make your tube as long as the sub will take and make you water tight areas as small as possible? I always forget I'm pushing up all that deck and conning tower. Now I can see if someone got carried away doing a super detail on one of these plastic kit subs converted to RC it could really turn out bad.

On another note: someone told me on the RCgroups sub forum to use the fore planes for control and the aft planes for a sub leveler. Valid idea or not? As I'm starting over I'm pretty flexable.

[JWLaRue]

Re: I need help with Warship Hulls Unlimited type IX

Making the pressure hull "too big" won't affect the required size of the ballast tank.....unless the PH is above the waterline. Of course if the PH is too large to install the desired size of ballast tank.....that would be different!

-Jeff

[flying jeep]

Re: I need help with Warship Hulls Unlimited type IX

That's exactly what happened. I ran out of scale hull to fill with balast tank.

[greenman407]

Re: I need help with Warship Hulls Unlimited type IX

OK , try this. Remove your lead keel. Using rubber bands, one toward the front and one toward the rear on the outside of the hull attach small lead weights (like you by in a airplane hobby store). Add them slowly while flooding the ballast tanks. Add just enough to get your conning tower to submerge leaving about a half inch to 1 inch still sticking out of the water. Thats called submerged trim and thats whats most important. With it in this condition your dive planes will force it under. Now surface.Now whatever waterline she comes up to is what youll have to live with until you lighten the load or increase volume of ballast tanks or decrease pressure hull displacement. If it works to your satisfaction with the weights held on by the rubber bands then carefully record their position and quantity and then silicone them inside your hull in the same locations.

[flying jeep]

Re: I need help with Warship Hulls Unlimited type IX

That's almost exactly how I came about the weight of the lead keel. Using large lead washers I got the sub to just float. Then I melted the lead into a keel shape and rubber banded it on the bottom. With the keel attached and balast tanks empty, I can just get decks awash. Not very scale like for a WWII sub. I guess it would be okay for a modern "boomer"

[greenman407]

Re: I need help with Warship Hulls Unlimited type IX

Well its not the end of the world as they say. At least you can operate it and enjoy it as it is. If a redesign is too much then use it as it is and then build another submarine using lessons learned.

[flying jeep]

Re: I need help with Warship Hulls Unlimited type IX

Yes, it did look very good just crusing around on the surface. But the battery is long dead, the radio is not even legal to use anymore, and the last time I tried to motor it up the speed controller was not working. Lost cause, start over.
Jay

[flying jeep]

Re: I need help with Warship Hulls Unlimited type IX

While looking for a book I thought I had on classic Mini Coopers, I'm in the market by the way, I found four pages I had printed from this site years ago about ballast tanks. Skip Asay is the author and it has shed light on my problem of ballast tanks for my sub. It was from issue 29 of the SCR and titled How It Works! I've been reading everything I could get my hands on about water displacement and bouyancy, but this little four pages tells you exactly how to figure out how much ballast tank you need. Skip, if you're out there, my hat is off to you.

Jay

[tmsmalley]

Re: I need help with Warship Hulls Unlimited type IX

Jay -
The Indy Admirals does indeed have a sub guru. Dave Hampton (past prez of the Indy Admirals) has been in subs since before the SubCommittee was invented. I know he'd be happy to talk to you.
Tim

[flying jeep]

Re: I need help with Warship Hulls Unlimited type IX

I know, I need to join and meet the guys. If any Admirals are out there please send me a PM and let me know when and where you meet.

Thanks,
Jay

[robert f.]

Re: I need help with Warship Hulls Unlimited type IX

Jay,

a few minutes of Googling brings you this:

http://www.indyadmirals.org/docs/2011%20Schedule.pdf

Regards,

Robert